1. Field of the Invention
The invention relates to the field of exercising machines, and in particular to exercising machines simulating a stepping or climbing action in which the rate of energy input into the exercise machine, or more generally the power output of the human exerciser, is monitored and the load of the exercising machine controlled to maintain power input into the machine or power output from the human exerciser more accurately monitored.
2. Description of the Prior Art
Stepping exercise machines are well known to the art and have been built with a large number of designs and control methodologies. Typical examples of prior art stair climbing or stepping exercise machines can be found in Robards, Jr. et al, xe2x80x9cExercise Apparatus for Simulating Stair Climbing,xe2x80x9d U.S. Pat. No. 5,135,447 (1992); Hennessey et al., xe2x80x9cExercise Machine and Transmission Therefor,xe2x80x9d U.S. Pat. No. 5,139,469 (1992); Bull, xe2x80x9cExercise Apparatus,xe2x80x9d U.S. Pat. No. 5,013,031 (1991); Stark et al., xe2x80x9cExercise Apparatus Having High Durability Mechanism for User Energy Transmission,xe2x80x9d U.S. Pat. No. 4,949,993 (1990); and Potts, xe2x80x9cStair Climbing Exercise Apparatus,xe2x80x9d U.S. Pat. No. 4,708,338 (1987). The type of mechanical linkages and arrangements to provide the stair climbing action, the types of load devices as well as how those loads are controlled varies considerably over the art and different examples can be found in each of these references.
For example, in Sweeney, Jr., xe2x80x9cProgram Exerciser Apparatus and Method, xe2x80x9d U.S. Pat. No. 4,358,105 (1982), a stepper is described which uses a pony brake as a load in combination with a flywheel in which the speed of the flywheel is controlled by a computer. In such devices, the energy rate or power of the exerciser, or at least the power input into the exercise machine by the human exerciser, varies considerably, not only over the course of a given exercise session, but dramatically between one exerciser and the next for the same speed control setting.
Such stepper machines usually include various handrails to allow the exerciser to steady himself or herself on the machine while exercising. It is almost a universal characteristic that exercisers will tend to lean on or support themselves in part on these handrails to effectively lighten or offset their weight on the stepping pedals and hence to decrease the amount of work that they put into the machine at a given speed setting.
Furthermore, the amount of energy expended by a petite 98-pound girl operating at a given speed, for example 20 steps per minute, is substantially different than the same amount of energy input into the machine by a 285-pound male line-backer also exercising at the rate of 20 steps per minute.
In addition, it must be kept in mind that in terms of health and exercise physiology, the important parameter is not the energy which is input into the machine, but rather the energy which the human user actually expends during the exercise. Only a small fraction of the energy burned in the human body ends up in measurable energy input into the exercise machine. By far, the greater amount of energy or calories burned is lost to sweat, body heat radiation and respiration.
Therefore, what is need is some type of a stepping or exercising machine and method for controlling the exercising machine whereby true, quantitative values of power input into the machine can be monitored and the machine load controlled to maintain those power levels substantially constant, and also to control the machine load relative to actual body power consumption during exercise.
The invention is an exercise machine for providing power controlled exercise for a user comprising an exercise input unit to transform human exercise into a predetermined motive force. A dynamically controllable load is driven by the predetermined motive force. A sensing circuit senses the power coupled into the load through the exercise input unit. A control circuit controls the dynamically controllable load to require a user-selected amount of power to be provided to the exercise input unit by the user. As a result, the exercise machine operates to provide a substantially constant and quantifiable energy rate of exercise.
The exercise machine further comprises a base chassis in which the exercise input unit is disposed. A wrap-around hand railing coupled to the base chassis completely encircles the user except at an entry position. An input/output display module is coupled to the control circuit and is integrally formed with the wrap-around hand railing. The base chassis, wrap-around hand railing, and display module have an overall geometric envelope characterized by a width. The width has a dimension less than a standard residential door width to facilitate ease of movement of the exercise machine.
The circuit for controlling the load controls the load to maintain power input by the user into the exercise input unit at a predetermined approximate power level, or to maintain metabolic power of the user at a predetermined level when the user is inputting power into the exercise input unit.
In the illustrated embodiment the exercise input unit is a stepper, and the dynamically controllable load is an alternator. The alternator has field coils, and the circuit for controlling the load comprises a field control circuit for pulse width modulating the field coils of the alternator.
The dynamically controllable load more generally comprises a circuit for generating electrical power and a variable dissipative electrical load coupled to the circuit for generating electrical power.
The dynamically controllable load generates a sensible electrical output and the circuit for sensing power coupled into the load comprises a computer having an input coupled to the sensible output of the dynamically controllable load. The computer generates an output coupled to the dynamically controllable load to maintain the load at a predetermined level of power input.
The exercise machine further comprises a tachometer for sensing rate of mechanical power input into the exercise input unit. The tachometer is coupled to the control circuit so that the control circuit controls the load in response to the tachometer and to the sensing circuit. The sensing circuit""senses time dependent output voltage and output current generated by the alternator.
The dynamically controllable load generates electrical power and is the sole source of electrical power for the sensing circuit and control circuit. The exercise machine further comprises a battery circuit to provide startup field coil power to the alternator prior to the alternator having reached a predetermined output level. The battery circuit further powers the sensing circuit and control circuit for a predetermined time-out period after the alternator ceases to generate electrical power. The control circuit also disconnects the battery circuit from the sensing circuit and control circuit after elapsed of the predetermined time-out period.
The controllable load provides electrical charging power to the battery circuit to recharge the battery circuit so that the exercise machine is entirely self-powered by the user.
The invention is also characterized as a method for controlling an exercise machine comprising the steps of transforming motion of a user into a predetermined mechanical motive force, and dynamically resisting the predetermined motive force to maintain an approximately constant power input into the exercise machine. As a result, quantifiably controlled energy rate levels of exercise are achieved.
The step of transforming user motion into the predetermined motive force comprises the step of converting stepping motion into motion of a shaft, and generating electrical power from rotation of the shaft at a predetermined magnitude. In the illustrated embodiment the step of generating electrical power at a predetermined magnitude comprises the step of generating electrical power in an alternator having current in its field coils pulse width modulated in response to sensed current and voltage output from the alternator to maintain the predetermined magnitude of power.
The method may further comprise the step of selectively shunting a portion of current from the alternator into a dissipative load to further control the step of dynamically resisting the motive force.
The invention can also be characterized as an improvement in an exercise machine for providing exercise for a user. The exercise machine has an electrically OFF and an electrically ON operational status and comprises an input unit to transform human exercise into a motive force. A load, which in the preferred embodiment is electromechanical, is driven by the motive force. An input/output circuit provides a readout to the user. The improvement comprises a power-up circuit for providing electrical power to the input/output circuit upon initiation of normal use of the exercise machine so that operational status of the exercise machine is changed from the electrically OFF status to the electrically ON status without the assistance of any external source of electrical power.
The invention is also an improvement in a stepper having a pedal pivotally coupled to a four-bar linkage where the four linkage is coupled to a frame and the frame disposed on a supporting floor. The four-bar linkage comprises an upper arm pivotally coupled to the pedal at a first pivot point and to the frame at a second pivot point. A pedal arm is pivotally coupled to the pedal at a third pivot point spaced from the first pivot point and to the frame at a fourth pivot point spaced from the second pivot point. The spacing between the first and third pivot points and between the second and fourth pivot points is arranged so that an imaginary line extending between the first and second pivot points of the upper arm is nonparallel to an imaginary line extending between the third and fourth pivot points. The pedal is oriented at least in one position of the four-bar linkage nonparallel to the floor.
The pedal defines an angle of orientation with respect to the floor, and is capable of assuming an up position and a down position. The four-bar linkage varies the angle of orientation of the pedal as the pedal is moved between the down position and the up position.
The invention is still further a method of providing a varied exercise session in a variably loaded exercise machine comprising the steps of providing a prestored sequence of loading conditions for the exercise machine and entering the prestored sequence of loading conditions at an arbitrary entry point within the sequence. The exercise machine is loaded according to the prestored sequence starting with the arbitrarily entered entry point and following the loading conditions in the prestored sequence.
The prestored sequence of loading conditions has a first loading condition and a last loading condition in the sequence and further comprises the step of loading the exercise machine with the first loading condition and contingently subsequent ones of the prestored sequence after the exercise machine has been loaded by the last loading condition.
The method further comprises the steps of detecting a machine startup event indicative of an operational state of the exercise machine and detecting a user selected time for the entry point. A time lapse between detection of the machine startup event and the user selected time is determined in order to select a beginning one of the loading conditions in the prestored sequence of loading conditions as an initial loading condition imposed on the exercise machine. The sequence of loading conditions are a multiple of a predetermined number and wherein the entry point is determined by taking the elapsed time modulo the predetermined number to give a remainder which identifies the initial loading condition.
The invention may be better visualized by now turning to the following drawings wherein like elements are referenced by like numerals.